Method for treating mineral slurries with a biocide

ABSTRACT

A method of treating mineral slurries to inhibit bacterial growth includes adding an effective amount of one or more of sodium N-methyldithiocarbamate or methylammonium monomethyldithiocarbamate to the mineral slurry to inhibit bacterial growth.

FIELD OF THE INVENTION

The invention relates to the treatment of mineral slurries with abiocide, and in particular, to a treatment using an effective amount ofone or both of sodium N-methyldithiocarbamate and methylammoniummonomethyldithiocarbamate in the mineral slurry to inhibit bacterialgrowth.

BACKGROUND ART

The use of biocides in mineral slurries is well known. Biocides are usedin mineral slurries to inhibit bacterial growth. Typically, biocides areadded both during the manufacturing process and as preservatives in thefinal product. The product selection and dosage is normally based onextensive laboratory analysis to measure product efficacy andinteractions with other slurry components. Additionally, regulatory,safety and customer requirements also impact the choice of biocide.

There are a limited number of biocides with the appropriate EPA and FDAclearances for use in mineral slurries to inhibit bacteria growth. Theseproducts primarily include glutaraldehyde (Glute), 1,2benzithiazolin-3-one (BIT),tetrahydro-3-5-methyl-2H-1,3,5-thiadizine-2-thione (thione or dazomet),isothiazoline (Iso), bronopol (BNPD), orthophenyl phenate (OPP), or2,2-dibromo-3-nitrilopropionamide (DBNPA).

A particular one of these biocides is sold under the name BCS 3243whichis tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione, which is alsoknown in the industry as thione or dazomet (hereinafter thione) CAS#53-74-4 and EPA Reg. No. 1448-103-82760. This material is designed topreserve clay slurries, adhesives, coatings and high viscositysuspensions. Thione is sold in dry, caustic based solution and waterbased emulsion forms. For preservation of slurries and high viscositysuspensions, thione is typically added at a point in the processingsystem where there will be sufficient time and agitation for good mixingand dispersion. Preferred amounts are at levels of 0.04-0.45%, byweight, based on the total formulation in slurries of kaolin, starch,clay, calcium carbonate, or titanium dioxide. Thione also hasapplications in paper coatings; high viscosity suspensions (e.g.,polymers, silica-polymer combinations); polyvinyl alcohol/polyvinylacetate-based adhesives; starch-based adhesives; in oilfieldapplications and dextrin-based adhesives. The exact amount of materialto be added for the preservation of any given formulation will depend onthe components and local storage time and conditions. Dosage rates arenormally determined by actual tests.

These known biocides have numerous limitations as they can be sensitiveto slurry pH and temperature, they can impact quality, they have odorand can have high VOC's, the efficacy can be insufficient, and they canbe expensive. Glutaraldehyde can be problematic because it is hazardousto handle and has environmental concerns. Moreover, it containsaldehydes, is the least cost efficient biocide, and is odiferous. BITand ISO are also limited in applications based on slurry pH,interactions with other slurry components, and temperature. Bronopol issusceptible to high process temperatures, pH, and interaction withslurry components. Thione is a good broad spectrum biocide and isversatile but has limited application because it creates odor and hasother health and safety issues due to the presence of formaldehyde.

There is a need for additional and more versatile biocides to addresschanging slurry formulations, regulatory constraints, slurryinteractions, efficacy, odor, and be able to mitigate many of theseproblems.

SUMMARY OF THE INVENTION

One object of the invention is the treatment of mineral slurries withbiocides.

Another object of the invention is the treatment of mineral slurrieswithout having to use a biocide that has formaldehyde.

Another object of the invention is the use of biocides in applicationsrelated to oil fields.

In satisfaction of the objects and in one aspect, the invention is animprovement in the known method of treating a mineral slurry with abiocide to inhibit bacterial growth. The improvement is adding aneffective amount of one or more of sodium N-methyldithiocarbamate ormethylammonium monomethyldithiocarbamate to the mineral slurry toinhibit bacterial growth.

The effective amount further comprises up to 0.45% by weight, based onthe total formulation in slurries, with preferred ranges being 500-1500ppm in the slurry being treated.

The mineral slurry can be any known type that is typically treated withbiocides, including but not limited to slurries containing water and oneor more of a kaolin, starch, a clay, calcium carbonate, or titaniumdioxide. The clay can be a kaolin clay and the calcium carbonate can bea ground type or precipitated calcium carbonate. The water can be freshwater or reclaimed water.

The inventive method can include the combination of the one or more ofsodium N-methyldithiocarbamate or methylammoniummonomethyldithiocarbamate and an effective amount of another biocideselected from the group consisting of glutaraldehyde, 1,2benzithiazolin-3-one,tetrahydro-3-5-methyl-2H-1,3,5-thiadizine-2-thione, isothiazoline,bronopol, 2,2-dibromo-3-nitrilopropionamide, and orthophenyl phenate.

The invention is also an improvement in the treating of water used inoil field applications, wherein methylammonium monomethyldithiocarbamatecan be used as an effective biocide in these types of applications. Theinventive method in this aspect encompasses any oil field applicationinvolving water and the need for a biocide. Examples of such oil fieldapplications where biocide treatment of water would be required includeoil well drilling with oil field drilling muds, well stimulation,fracturing fluids, oil field processing applications, oil field watertreatment systems, oil and gas productions and transmission pipelinesand systems, gas storage fields and equipment; such as steam-injectionwater holding tanks, flood water, injection water, holding pond water,disposal-well water, water holding tanks, fuel storage tanks and relatedrefinery and oil field closed, industrial recirculating water handlingand the like.

The concentrations used in will vary depending on water and bacteriaconcentration. Routine laboratory testing and procedures are readilyavailable to determine the minimum quantities necessary whereas themaximum dosages are normally regulated by economics.

The invention is also an improvement in methods of treating adhesives,coatings, and high viscosity suspensions to inhibit bacterial growth byadding an effective amount of a biocide to the coatings, adhesives, andhigh viscosity suspensions. The improvement comprises comprising addingan effective amount of one or more of sodium or potassiumN-methyldithiocarbamate and methylammonium monomethyldithiocarbamate toone or more of the coatings, adhesives, and high viscosity suspensionsto inhibit bacterial growth. The effective amount can comprise 200-4500ppm weight based on the total formulation. An additional biocide can beused in connection with this application, these additional biocidesincluding glutaraldehyde,tetrahydro-3-5-methyl-2H-1,3,5-thiadizine-2-thione,2,2-dibromo-3-nitrilopropionamide, bronopol, orthophenyl phenate, ortetra-kis-hydoxymethyly-phosphonium sulfate (THPS).

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a significant improvement in the treatment ofmineral slurries with a biocide through the use of an effective amountof one or both of sodium N-methyldithiocarbamate and methylammoniummonomethyldithiocarbamate. Hereinafter, sodium N-methyldithiocarbamateand methylammonium monomethyldithiocarbamate are referred to as metamsodium and MDTCMA, respectively, for simplicity.

The use of either metam sodium or MDTCMA provides a significantadvantage in the field of treating mineral slurries with biocides andthe invention addresses a number of problem issues in mineral slurrypreservation. Both metam sodium and MDTCMA produce the break-downcomponent methylisothiocyanate (MITC), which provides the efficacy ofthe biocide. MITC is also the break-down component in thione. Therefore,metam sodium or MDTCMA work just as well as the thione biocide from anefficacy standpoint. More importantly, metam sodium and MDTCMA do notcontain formaldehyde or other aldehydes. In essence, using either metamsodium or MDTCMA represents a non-formaldehyde based microbiocidechemistry for preserving mineral slurries. The inventive method can alsobe characterized as employing a non-oxidizing or non-halogenated basedchemistry whose antimicrobial activity is not based on producingaldehyde or formaldehydes. Without these presence of these harmfulcomponents in thione, the use of metam sodium or MDTCMA as a biocidepermits a broader use in mineral slurry preservations. Essentially metamsodium and MDTCMA provide the efficacy of thione without the odor orsafety issues of thione. Both metam sodium and MDTCMA are cost effectivealternatives to existing approved mineral slurry biocides.

The concentration of metam sodium or MDTCMA in a given slurry willdepend on a number of factors. Broadly, the amount of either metamsodium or MDTCMA for a given slurry should be an amount that will beeffective to inhibit bacterial growth in the selected mineral slurry.Examples of such amounts include a concentration range of up to 0.04 to0.45% by weight, with a preferred range of 500-1500 ppm of the biocidein the slurry being treated.

The mineral slurries suitable for treatment with metam sodium and MDTCMAare those that are normally treated with biocides. Examples of theseslurries include water containing kaolin, starches, clays, calciumcarbonate (both ground and precipitated), and titanium dioxide. Thesetypes of slurries are exemplary only and any mineral slurry needingbiocidal treatment is a candidate to use metam sodium or MDTCMA as abiocide, either alone or in combination with a known biocide.

Typically, metam sodium is made in an aqueous solution at aconcentration range of 27-42%. Metam potassium is also a commerciallyrecognized alternative to the metam sodium and varies primarily in theuse of potassium hydroxide versus sodium hydroxide in the manufacturingprocess. MDTCMA is also available in an aqueous solution inconcentrations ranging from 45-50%. Both metam sodium and MDTCMA areavailable commercially from a number of different sources and theirCAS-Nos are 137-42-8 and 21160-95-2, respectively.

In use as a biocide for treatment of mineral slurries, the biocides ofmetam sodium and MDTCMA can be used in the same manner of known biocidessuch as thione, glute, and the like. One example of use is shown abovein connection with thione sold under the name BCS 3243. However, this isonly one example of how a biocide is to be used to preserve mineralslurries and any other known ways to employ a biocide in the treatmentof a mineral slurry can be used in connection with metam sodium andMDTCMA. U.S. Pat. No. 3,282,715 to Sawyer et al. is an example of usingthione in a clay slurry for preservation purposes. U.S. Pat. No.4,997,550 to Cobb et al. is another example of treating a mineral slurryand adding a biocide prior to the flotation step. Both of these patentsare incorporated by reference herein.

The inventive method can include the combination of the one or both ofsodium N-methyldithiocarbamate and methylammoniummonomethyldithiocarbamate and an effective amount of another biocideselected from the group consisting of glutaraldehyde, 1,2benzithiazolin-3-one,tetrahydro-3-5-methyl-2H-1,3,5-thiadizine-2-thione, isothiazoline,bronopol, 2,2-dibromo-3-nitrilopropionamide, and orthophenyl phenate.

A number of comparative tests were performed to compare the efficacy ofmetam sodium and MDTCMA to other biocides. The results of these studiesare shown in tabular form in Tables 1-3 and described below

In the comparative testing, dry kaolin was mixed with water to achieve a65% solid slurry material. This material contained no biocide. Theslurry was then split into 200 gram aliquots and dosed with differentbiocides at different concentration as shown in Tables 1-3. All sampleswere kept at 50° C. until the end of the testing, which was up to 28days.

A number of different and known biocides were used in the study and theyinclude glutaraldehyde (glute), 1,2 benzithiazolin-3-one (BIT),tetrahydro-3-5-methyl-2H-1,3,5-thiadizine-2-thione (thione),isothiazoline (ISO), bronopol (BNPD) or orthophenyl phenate (OPP). Forshorthand purposes, the study refers to the tradename of the biocide,which is found in the above listing of the biocides. Metam sodium isdesignated as SMDC and MDTCMA is used without change

The protocol for the testing of each sample is as follows:

-   -   1) dosed with a recorded level of biocide;    -   2) mixed for 24 hours contact time and plated using standard        method agar for bacterial growth;    -   3) remixed daily for 1 hour and retested for bacterial growth at        Day 3;    -   4) remixed daily for 1 hour and retested for bacterial growth at        Day 7;    -   5) remixed daily for 1 hour and retested for bacterial growth at        Day 14;    -   6) on day 20, samples were split into two containers: one        container was inoculated (or challenged) with ˜10⁵ cfu/ml        bacteria, the other was left “as treated”, the challenge        material was obtained from a contaminated kaolin product and is        assumed to be representative of the types of bacteria that are        seen in the kaolin industry, and the two sets of samples were        prepared for Day 21 testing;    -   7) both sets were remixed daily for 1 hour and retested for        bacterial growth at Day 21; and    -   8) both sets remixed daily for 1 hour and retested for bacterial        growth at Day 28.

Different contact times were used to see how quickly the bacterialpopulation was effected by the biocide.

Table 1 compares a kaolin/BIT slurry with the biocides of metam sodiumor MDTCMA. The concentrations of the biocide in ppm in the sample areshown. The contact time for the biocide and the number of colonies isreported as cfu/ml for the control and the tested biocide. What Table 1shows is that the biocides of metam sodium or MDTCMA performed at leastas well as the BIT biocide at a concentration of 500 ppm when measuringlog reduction and was far superior for a concentration of 1000 ppm.

TABLE 1 Contact Time 1 day 3 day 7 day Chemistry ppm cfu/mL Log Redcfu/mL Log Red cfu/mL Log Red Control 35,000,000 56,000,000 39,000,000Kathon/BIT Blend 500 11,780,000 0 1,640,000 2 100,000 3 MDTCMA 50013,140,000 0 1,880,000 1 40,000 3 1000 7,060,000 1 1,680,000 2 1,000 542% SMDC 500 24,340,000 0 2,600,000 1 30,000 3 1000 16,880,000 02,200,000 1 1,000 5

Table 2 shows additional comparative testing, which lasted for 28 days.Table 2 again compares the SDMC and MDTCMA used in Table 1 with adifferent set of biocides, including a combination of ISO and BIT, acombination of ISO and bronopol, glute, and thione. While glutaraldehydeis the best performer in Table 2, this Table also that either SDMC orMDTCMA provides comparable biocide efficacy as compared to knownbiocides, including thione, particularly at the 1000 ppm level ofconcentration.

TABLE 2 Contact Time 1 day 3 day 7 day 14 day Chemistry ppm cfu/mL LogRed cfu/mL Log Red cfu/mL Log Red cfu/mL Log Red Control 21,980,00026,690,000 44,000,000 53,000,000 CHALLENGE 1.5% ISO + 10% 400/40018,840,000 0 86,300 2 1,400 4 3,400 4 BIT 1.5% ISO + 10% 400/40011,780,000 0 530,000 2 6,800 4 4,200 4 Bronopol 50% Glute 400 100 5 1005 100 6 100 6 24% Thione 500 13,340,000 0 11,000 3 5,600 4 2,100 4 10006,670,000 1 6,800 4 2,600 4 1,200 5 MDTCMA 500 18,840,000 0 1,960,000 15,600 4 3,100 4 1000 14,520,000 0 7,000 4 3,200 4 2,500 4 42% SMDC 50019,630,000 0 780,002 2 4,000 4 3,000 4 1000 12,560,000 0 4,800 4 2,400 42,600 4 Contact Time 21 day 21 day Challenge 28 day 28 day ChallengeChemistry ppm cfu/mL Log Red cfu/mL Log Red cfu/mL Log Red cfu/mL LogRed Control 76,000,000 26,000,000 1.5% ISO + 10% BIT 400/400 4,000 489,000 3 3,300 4 102,000 2 1.5% ISO + 10% Bronopol 400/400 2,900 446,000 3 2,200 4 58,000 3 50% Glute 400 100 6 100 6 100 5 100 5 24%Thione 500 1,100 5 39,000 3 800 5 3,400 4 1000 300 5 900 5 200 5 1,500 4MDTCMA 500 1,800 5 73,000 3 2,500 4 65,000 3 1000 1,100 5 52,000 3 1,7004 32,000 3 42% SMDC 500 1,800 5 105,000 3 1,800 4 16,000 3 1000 900 559,000 3 900 4 16,000 3 Note: Day 20 - Samples split into two aliquotsand one aliquot challenged with 100,000 cfu/ml

Table 3 shows another series of comparisons, primarily between thioneand SDMC and MDTCMA. Here, the concentrations of the SDMC and MDTCMAwere increased to 1000 and 1500 ppm as compared to the 500-1000 ppm usedin Tables 1 and 2. Up to the 28 day testing (not challenge testing), theSDMC and MDTCMA performed on a par with the thione for biocideeffectiveness. For the challenge testing, MDTCMA still performedadequately but, under these conditions, SDMC was comparable to thioneand also the superior biocide as between SDMC and MDTCMA.

Table 3 uses SDMC and MDTCMA in lower amounts (500 ppm) in combinationwith other biocides. This testing reveals that the use of the loweramounts of SDMC and MDTCMA in combination with the known biocidesproduces a comparable biocide effectiveness as compared to the SDMC andMDTCMA used alone and in higher concentrations. However, the combinationof the SDMC and MDTCMA with other biocides does not seem to show anysynergistic effect.

TABLE 3 Contact Time 1 day 3 day 7 day 14 day Chemistry ppm cfu/mL LogRed cfu/mL Log Red cfu/mL Log Red cfu/mL Log Red Control 250,000 10,00027,000 200,000 CHALLENGE 24% Thione 500 3,300 2 100 2 100 2 100 3 1000100 3 100 2 100 2 100 3 MDTCMA 1000 100 3 100 2 100 2 100 3 1500 100 3100 2 100 2 100 3 42% SMDC 1000 200 3 100 2 100 2 100 3 1500 100 3 100 2100 2 100 3 1.5% ISO/MDTCMA 200/500 100 3 100 2 100 2 100 3 9%BIT/MDTCMA 200/500 7,000 2 100 2 100 2 100 3 10%/BNPD/MDTCMA 200/500 1003 100 2 300 2 100 3 50% Glute/MDTCMA 200/500 100 3 100 2 100 2 100 31.5% ISO/42% SMDC 200/500 100 3 100 2 100 2 100 3 9% BIT/42% SMDC200/500 1,000 2 100 2 100 2 100 3 10%/BNPD/42% SMDC 200/500 1,100 24,000 0 100 2 100 3 50% Glute/42% SMDC 200/500 100 3 100 2 100 2 100 3Contact Time 21 day 21 day Challenge 28 day 28 day Challenge Chemistryppm cfu/mL Log Red cfu/mL Log Red cfu/mL Log Red cfu/mL Log Red Control7,000 20,210,000 8,400 23,500,000 24% Thione 500 100 2 100 5 100 2 100 51000 100 2 100 5 100 2 100 5 MDTCMA 1000 100 2 196,000 2 100 2 3,680,0001 1500 100 2 18,200 3 100 2 2,300,000 1 42% SMDC 1000 100 2 384,000 2100 2 3,000,000 1 1500 100 2 100 5 100 2 100 5 1.5% ISO/MDTCMA 200/500100 2 424,000 2 100 2 4,000,000 1 9% BIT/MDTCMA 200/500 100 2 31,400 3100 2 3,400,000 1 10%/BNPD/MDTCMA 200/500 100 2 471,000 2 100 22,800,000 1 50% Glute/MDTCMA 200/500 100 2 500,000 2 100 2 2,500,000 11.5% ISO/42% SMDC 200/500 100 2 600,000 2 100 2 2,600,000 1 9% BIT/42%SMDC 200/500 100 2 67,000 2 100 2 4,000,000 1 10%/BNPD/42% SMDC 200/500100 2 500,000 2 100 2 3,500,000 1 50% Glute/42% SMDC 200/500 100 2392,000 2 100 2 3,000,000 1 Note: All samples will be kept at 50 C. forthe duration of the experiment to mimic process temperatures. Day 20 -Samples split into two aliquots and one ailquot challenged with ~100,000cfu/ml Lowest sample dilution before plating was 1:100

In general, the results of the studies show that after inoculation, bothlevels of thione and the highest level of metam sodium were the mosteffective biocides. However, MDTCMA also was an effective biocide aswell and could easily replace thione as a mineral slurry biocide.Replacing thione with either metam sodium or MDTCMA eliminates thedrawbacks of odor and the presence of formaldehydes as is the case withthione. Therefore, both MDTCMA and SMDC are viable candidates for use asa biocide in the treatment of mineral slurries, for example, the kaolinor calcium carbonate industries, with metam sodium providing a slightlybetter biocide effectiveness than MDTCMA based on the studies discussedabove.

It should be understood that metam potassium, i.e., potassiumN-methyldithiocarbamate, would be expected to provide the same biocidalefficacy as sodium N-methyldithiocarbamate and in the sameconcentrations as disclosed for sodium N-methyldithiocarbamate in theapplications disclosed herein. As such, metam potassium can be used withor in place of metam sodium or MDTCMA in biocide applications. Thesecompounds can be referred to as sodium or potassiumN-methyldithiocarbamate or metam sodium/potassium.

While MDTCMA has been shown to be an effective biocide in mineral slurryapplications, it is also believed to have use in oil field applications.These applications include oilfield drilling muds and workover orcompletion fluids; for control of slime-forming and/or spoilage bacteriaand oilfield water treatment and water floods; for control ofslime-forming and/or spoilage bacteria. Additional uses for the MDTCMAin the context of oil field applications include those applicationsdiscussed in the background art section above.

In these oil field applications, the MDTCMA would be used just likeother biocides would be used in these applications. As these methods ofuse are well known, a detailed description of these methods is notnecessary for understanding of the invention. As an example, theappropriate amount of MDTCMA would be used to get the desiredconcentration in a drilling fluid system being treated, e.g., so manygallons of a solution of MDTCMA per barrel of drilling fluid forexample. The solution of MDTCMA can then be added to the fluid systemwhere appropriate. For example, the solution could be added to a mud pitwhere drilling fluid is circulating. As the total volume increases, dueto greater well depth, add additional biocide maintain the properconcentration. Because of the wide variation in drilling mud compositionand bacterial contamination, greater or lesser amounts of the solutionmay be used. Examples of the waters or water systems needing biocidetreatment in oil field operations include waste waters, drilling muds,workover or completion fluids, hydrolytic fracturing fluids, slickwaterfracturing fluids and borate crosslinked guar fluids. While theconcentration of MDTCMA is dependent on the water being treated,concentrations are based on laboratory testing but may range from 200ppm to 4500 ppm with preferred ranges of 2500 ppm.

Metam sodium/potassium and MDTCMA can also be used as a biocide whentreating one or more of adhesives, coatings, and high viscositysuspension, e.g., paper coatings, polymers and silica-polymercombinations as suspensions, polyvinyl alcohol/polyvinyl acetate-basedadhesives, starch based adhesives, and dextrin-based adhesives. Thetreatment of these materials using metam sodium/potassium and MDTCMA canfollow the same protocols that are used when thione is used as a biocidein these applications. Since these protocols are well known, a furtherdescription is not necessary for the understanding of the invention. Thelevels of concentration for these applications and determinationsthereof are also expected to match the ranges set out above for mineralslurry applications. The effective amount can range from 200-4500 ppmweight based on the total formulation. An additional biocide can be usedin connection with this application, these additional biocides includingglutaraldehyde, tetrahydro-3-5-methyl-2H-1,3,5-thiadizine-2-thione,2,2-dibromo-3-nitrilopropionamide, bronopol, orthophenyl phenate, ortetra-kis-hydoxymethyly-phosphonium sulfate (THPS).

The mineral slurries using the metam sodium or MDTCMA can include otherknown additives such as surfactants, solubilizing agents, and the likethat would be present in the slurries. Likewise, waters being treated inoil field applications or in conjunction with making coatings,adhesives, and high viscosity suspensions could also contain knownadditives.

As such, an invention has been disclosed in terms of preferredembodiments thereof which fulfills each and every one of the objects ofthe present invention as set forth above and provides a new and improvedway to treat mineral slurries to inhibit bacterial growth by the use ofone or both of sodium N-methyldithiocarbamate and methylammoniummonomethyldithiocarbamate.

Of course, various changes, modifications and alterations from theteachings of the present invention may be contemplated by those skilledin the art without departing from the intended spirit and scope thereof.It is intended that the present invention only be limited by the termsof the appended claims.

1. In a method of treating a mineral slurry to inhibit bacterial growthby adding an effective amount of a biocide to the mineral slurry, theimprovement comprising adding an effective amount of one or more ofsodium or potassium N-methyldithiocarbamate and methylammoniummonomethyldithiocarbamate to the mineral slurry to inhibit bacterialgrowth.
 2. The method claim 1, wherein the effective amount furthercomprises 0.04-0.45% by weight based on the total formulation.
 3. Themethod of claim 1, wherein the mineral slurry further comprises a slurrycontaining water and one or more of a starch, a clay, calcium carbonate,or titanium dioxide.
 4. The method of claim 3, wherein the clay is akaolin clay and the calcium carbonate is a ground or precipitatedcalcium carbonate.
 5. The method of claim 3, wherein the water is freshwater or reclaimed water.
 6. The method of claim 1, further comprisingadding an effective amount of an additional biocide selected from thegroup consisting of glutaraldehyde, 1,2 benzithiazolin-3-one,tetrahydro-3-5-methyl-2H-1,3,5-thiadizine-2-thione, isothiazoline,bronopol, 2,2-dibromo-3-nitrilopropionamide, or orthophenyl phenate. 7.In a method of treating water used in an oil field application toinhibit bacterial growth by adding an effective amount of a biocide tothe water, the improvement comprising adding an effective amount ofmethylammonium monomethyldithiocarbamate to the water to inhibitbacterial growth.
 8. The method claim 7, wherein the effective amountfurther comprises 200-4500 ppm weight based on the total formulation. 9.The method of claim 7, wherein the water further comprises oil drillingfluids, oil field waste water, drilling muds, workover or completionfluids, hydraulic fracturing fluids, slickwater fracturing fluids orborate crosslinked guar fluids.
 10. In a method of treating adhesives,coatings, and high viscosity suspensions to inhibit bacterial growth byadding an effective amount of a biocide to the coatings, adhesives, andhigh viscosity suspensions, the improvement comprising adding aneffective amount of one or more of sodium or potassiumN-methyldithiocarbamate and methylammonium monomethyldithiocarbamate toone or more of the coatings, adhesives, and high viscosity suspensionsto inhibit bacterial growth.
 11. The method claim 10, wherein theeffective amount further comprises 200-4500 ppm weight based on thetotal formulation.
 12. The method of claim 10, further comprising addingan effective amount of an additional biocide to the one or more of thecoatings, adhesives, and high viscosity suspensions, the biocideselected from the group consisting of glutaraldehyde,tetrahydro-3-5-methyl-2H-1,3,5-thiadizine-2-thione,2,2-dibromo-3-nitrilopropionamide, bronopol, orthophenyl phenate, ortetra-kis-hydoxymethyly-phosphonium sulfate.
 13. The method of claim 10,wherein the coatings comprise paper coatings.
 14. The method of claim10, wherein the adhesives comprise polyvinyl alcohol/polyvinylacetate-based adhesives, starch based adhesives, and dextrin-basedadhesives.
 15. The method of claim 10, wherein the high viscositysuspensions comprise polymers and silica-polymer combinations.
 16. Themethod of claim 7, further comprising adding an effective amount of anadditional biocide selected from the group consisting of glutaraldehyde,1,2 benzithiazolin-3-one,tetrahydro-3-5-methyl-2H-1,3,5-thiadizine-2-thione, isothiazoline,bronopol, 2,2-dibromo-3-nitrilopropionamide, or orthophenyl phenate. 17.The method of claim 7, wherein the water is fresh water or reclaimedwater.